Why Your Heat Pump Keeps Going Into Defrost Mode

Heating services in Asheville, NC

If you use a heat pump to heat your Asheville, NC home, you may notice it entering into defrost mode just when you need it most. In defrost mode, heat pumps automatically reverse their operations. They become functionally identical to air conditioners, and they transfer warm indoor air outside. Although this may seem counterproductive, when outdoor temperatures are especially cold, this manner of operation ensures that heat pump condenser coils don’t freeze. Read on to learn more about defrost mode on heat pumps and to determine whether there’s an underlying problem with yours.

Excessively Cold Temperatures and Your Heat Pump

In winter and during the daylight hours, outside conditions in Asheville are ideal for heat pump use. These units source heat from the outdoor air and route it inside. With average low temperatures rarely dipping below 40 degrees Fahrenheit, there’s plenty of heat to source. However, at night, Asheville temperatures often fall below freezing. When this occurs, your heat pump could struggle to source enough warmth. More importantly, the condenser coil in your heat pump may begin icing.

In this situation, an automatic shift into defrost mode is a protective measure. Most heat pumps will continue operating in defrost mode until the temperature of their condenser coils reaches at least 57 degrees Fahrenheit. This usually takes between 5 and 15 minutes.

What If My Heat Pump Goes Into Defrost Mode Too Often?

During an especially cold winter, your heat pump could spend a lot of time in defrost mode. If it does, this is a strong indication that the model you own is incapable of providing efficient, whole-house heating during severe weather. If your heat pump is nearing the end of its lifespan, this is a great time to replace it with a high-performance model. High-performance heat pumps can continue sourcing adequate outside heat even when outdoor temperatures are as low as five degrees Fahrenheit. Without a higher-performing heat pump, you may need a supplementary heating solution.

Defrost Mode Could Be a Sign of Functional Problems

Even when heat pumps are capable of performing in excessively low temperatures without having their coils freeze over, they could still enter into defrost mode. Common causes for this include:

  • Faulty thermostats
  • Faulty or extremely dirty condenser coils
  • Refrigerant leaks
  • Faulty reversing valves
  • Lower-than-required fan operating speeds

As such, it’s a good idea to have your heat pump professionally inspected if it starts switching to defrost mode with increasing frequency.

Since 2007, we’ve been providing superior heating, cooling, electrical, and geothermal services to residents of Asheville, NC and the surrounding area. We also provide indoor air quality services and preventative maintenance agreements. To schedule an appointment, get in touch with 1st Choice Service Group Heating & Air now.